Apparatus and method for providing a confined liquid for immersion lithography

ABSTRACT

A method for processing a substrate is provided which includes generating a meniscus on the surface of the substrate and applying photolithography light through the meniscus to enable photolithography processing of a surface of the substrate.

CROSS REFERENCE TO RELATED APPLICATION

This is a continuation-in-part of a co-pending U.S. patent applicationSer. No. 10/606,022, from which priority under 35 U.S.C. § 120 isclaimed, entitled “SYSTEM AND METHOD FOR INTEGRATING IN-SITU METROLOGYWITHIN A WAFER PROCESS” filed on Jun. 24, 2003. The aforementionedpatent application is hereby incorporated by reference.

U.S. patent application Ser. No. 10,606,022 is also acontinuation-in-part of U.S. patent application Ser. No. 10/404,270 fromwhich priority under 35 U.S.C. § 120 was claimed, entitled “VERTICALPROXIMITY PROCESSOR” filed on Mar. 31, 2003 now U.S. Pat. No. 7,069,937which is a continuation-in-part of U.S. patent application Ser. No.10/330,843 from which priority under 35 U.S.C. § 120 was claimed,entitled “MENISCUS, VACUUM, IPA VAPOR, DRYING MANIFOLD” filed on Dec.24, 2002 now U.S. Pat. No. 7,198,055 which is a continuation-in-part ofU.S. patent application Ser. No. 10/261,839 from which priority under 35U.S.C. § 120 was claimed, entitled “METHOD AND APPARATUS FOR DRYINGSEMICONDUCTOR WAFER SURFACES USING A PLURALITY OF INLETS AND OUTLETSHELD IN CLOSE PROXIMITY TO THE WAFER SURFACES” filed on Sep. 30, 2002now U.S. Pat. No. 7,234,477.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to semiconductor wafer processing and,more particularly, to apparatuses and techniques for more effectivelyconducting patterning a photoresist in a photolithographic operation.

2. Description of the Related Art

The ability to work selectively on small well defined areas of asubstrate is paramount in the manufacture of semiconductor devices. Inthe continuing quest to achieve higher levels of performance and higherfunctional density of the semiconductor devices, the microelectronicsindustry is committed to applying new processes to further reduce theminimum feature sizes of the semiconductor devices.

FIG. 1 shows an example of a simplified photolithographic operation 20.In the operation 20, a light source 26 generates light which is passedthrough a reticle 28. Reticles are generally manufactured by depositinga chromium photomask on a glass plate that is transparent. The photomaskis then typically coated with a resist, and then a pattern is defined inthe resist by usage of a pattern generator. The resist is then developedafter which the photomask is chemically processed to remove everythingbut the pattern from the glass plate. To define a pattern in the resist,the pattern generator utilizes an electron beam to generate the featuresin the resist. The light passed though the reticle 28 may then pattern aphotoresist 24 that has been applied to a surface of the substrate 22.The photoresist may then be processed as known by those skilled in theart to generate the desired features on the substrate 22.

As feature sizes are reduced, the devices can become smaller or remainthe same size but become more densely packed. As such, advances inlithographic technologies used to pattern the semiconductor devices mustkeep pace with the progress to reduce feature sizes, in order to allowfor smaller and more dense semiconductor devices. In order to do this,the lithographic technology must increasingly improve its ability toresolve smaller and smaller line widths. The resolution limit is in goodpart determined by the wavelength of light used to pattern thephotoresist. Therefore one of the main ways to reduce the devicecritical dimensions (CD) through lithographic technologies has been tocontinually reduce the wavelength of the radiation used to expose thephotoresist to yield well-defined pattern profiles.

High resolution lithographic transmission becomes more of a challenge aswafers progress to higher density chips with shrinking geometries.Furthermore, as metallization interconnect technology transitions todual damascene processes, lithography techniques to pattern holes ortrenches in the dielectric become more critical and has a direct impacton yield and reliability. In particular, optical lithographic methodsutilizing shorter wavelengths are often utilized to pattern thephotoresist. For example, attempts to use wavelengths as low as 157 nmhave been made. Unfortunately, present optical lithographic methods andtools have to be changed to utilize this shorter wavelength.Regrettably, to change over to the 157 nm wavelength from a higherwavelength process, optical lithographic tools must generally be changedsuch as using different materials for optics and different lensconcepts, as well as changing the photomask materials.

Therefore, there is a need for a method and an apparatus that canutilize the same masks, resists, and lens concepts as existing systemsbut at the same time also provide the sharper pattern profile thatresults from using shorter wavelengths to pattern the photoresist.

SUMMARY OF THE INVENTION

Broadly speaking, the present invention fills these needs by providing amethod and apparatus for conducting photolithography in an optimal andeffective manner. It should be appreciated that the present inventioncan be implemented in numerous ways, including as a process, anapparatus, a system, a device or a method. Several inventive embodimentsof the present invention are described below.

In one embodiment, a method for processing a substrate is provided whichincludes generating a fluid meniscus to process the substrate where thefluid meniscus is constantly replenished with fluid by addition of thefluid into the fluid meniscus and by removal of the fluid from the fluidmeniscus by a vacuum. The method also includes applying the fluidmeniscus to a photoresist on a substrate surface and transmitting apatterned light to the photoresist on the substrate surface through thefluid meniscus.

In another embodiment, an apparatus for processing a substrate isprovided which includes a proximity head configured to generate a fluidmeniscus to facilitate patterning of a photoresist on a substratesurface where the fluid meniscus is constantly replenished with fluid byaddition of the fluid into the fluid meniscus and by removal of thefluid from the fluid meniscus by a vacuum. The apparatus also includes alithography lens structure at least partially defined within theproximity head where the lithography lens structure has a lithographylens in direct contact with the fluid meniscus during operation. Thelithography lens structure applies a patterned light from thelithography lens through the fluid meniscus to pattern the photoresiston the substrate surface.

In yet another embodiment, an apparatus for processing a substrate isprovided which includes a proximity head capable of generating a fluidmeniscus to process a substrate surface where the fluid meniscus isconstantly replenished with fluid by addition of the fluid into thefluid meniscus and by removal of the fluid from the fluid meniscus by avacuum. The apparatus further includes a light generating source withinthe proximity head where the light generating source is in directcontact with the fluid meniscus during operation. The light generatingsource applies a patterned light into and through the fluid meniscus.The patterned light has a first wavelength before entrance into thefluid meniscus and an effective wavelength when applied to thephotoresist through the fluid meniscus where the effective wavelength isshorter than the first wavelength.

In another embodiment, a method for processing a substrate is providedwhich includes generating a meniscus on the surface of the substrate andapplying photolithography light through the meniscus to enablephotolithography processing of a surface of the substrate.

In yet another embodiment, a photolithography apparatus is providedwhich includes a proximity head where the proximity head is capable ofgenerating a meniscus on a surface of a substrate. The apparatus alsoincludes a light source for applying photolithography light from theproximity head and through the meniscus where the photolithography lightcontacts the surface of the substrate to enable photolithographyprocessing.

The advantages of the present invention are numerous. Most notably, theapparatuses and methods described herein efficiently pattern photoresistin an immersion lithography operation by converting a wavelength of anoptical signal to a shorter effective wavelength. The shorter effectivewavelength may be generated using a proximity head with lithography lensthat is capable of directly contacting a fluid meniscus for transmittingoptical signals to a photoresist layer on a substrate surface throughthe fluid meniscus.

The proximity head with the photolithography lens can optimally managefluid application and removal from the wafer thereby generating thefluid meniscus through which the optical signal may be sent. The fluidmeniscus can be effectively moved without losing significant stabilityand in addition can be constantly replenished with new liquid therebyenhancing the photolithography process by significantly reducingbubbling and contamination within the fluid meniscus. Moreover, with theuse the fluid meniscus as described herein, contamination left on thewafer surface can be dramatically reduced. As a result, by using thefluid meniscus that can shorten the effective wavelength of the opticalsignal from the lithography lens, equipment such as lens and opticalapparatus generally used for longer wavelength photolithographic methodsmay be utilized to generate a much more precise and sharp patterningthan is generally available.

Other aspects and advantages of the present invention will becomeapparent from the following detailed description, taken in conjunctionwith the accompanying drawings, illustrating by way of example theprinciples of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be readily understood by the followingdetailed description in conjunction with the accompanying drawings. Tofacilitate this description, like reference numerals designate likestructural elements.

FIG. 1 shows an example of a simplified photolithographic operation.

FIG. 2 shows a wafer processing system in accordance with one embodimentof the present invention.

FIG. 3A illustrates a proximity head with lithography lens structure inaccordance with one embodiment of the present invention.

FIG. 3B shows a side view of an internal structure of the proximity headin accordance with one embodiment of the present invention.

FIG. 3C shows the proximity head in operation in accordance with oneembodiment of the present invention.

FIG. 4A illustrates a proximity head with an alternative exemplaryinlet/outlet configuration in accordance with one embodiment of thepresent invention.

FIG. 4B shows a side view of an internal structure of the proximity headwith the alternative exemplary inlet/outlet configuration in accordancewith one embodiment of the present invention.

FIG. 4C shows the proximity head conducting lithographic operations inaccordance with one embodiment of the present invention.

DETAILED DESCRIPTION

An invention for methods and apparatuses for processing a substrate isdisclosed. Specifically, an efficient and effective way of patterningphotoresist in a photolithographic operation is provided. In thefollowing description, numerous specific details are set forth in orderto provide a thorough understanding of the present invention. It will beunderstood, however, by one of ordinary skill in the art, that thepresent invention may be practiced without some or all of these specificdetails. In other instances, well known process operations have not beendescribed in detail in order not to unnecessarily obscure the presentinvention.

While this invention has been described in terms of several preferableembodiments, it will be appreciated that those skilled in the art uponreading the preceding specifications and studying the drawings willrealize various alterations, additions, permutations and equivalentsthereof. It is therefore intended that the present invention includesall such alterations, additions, permutations, and equivalents as fallwithin the true spirit and scope of the invention.

The figures below illustrate embodiments of an exemplary waferprocessing system where optimized photolithographic operations may beconducted. Specifically, the figures below illustrate embodiments of anexemplary wafer photolithographic system using proximity heads togenerate a fluid meniscus in a controlled environment that includes alithography lens structure located at least partially within a proximityhead. In one embodiment, the lithography lens may contact the fluidmeniscus and transmit patterned optical signals through the fluidmeniscus to a photoresist that has been applied to a surface of thesubstrate. It should be appreciated that application of a photoresistonto a substrate is well known to those skilled in the art. Bytransmitting the optical signals through the fluid meniscus and applyingthe optical signals to the photoresist, the wavelength of the opticalsignal may be changed to a shorter effective wavelength therebyresulting in more precise patterning of the photoresist. Consequently, amore precise way of patterning photoresist may be utilized to generatesmaller critical dimensions leading to smaller and more dense featureswithin a semiconductor wafer.

It should be appreciated that the systems described herein areexemplary, and that any other suitable type of configuration that wouldenable movement of the proximity head(s) into close proximity to thewafer may be utilized. In the embodiments shown, the proximity head(s)may move in any fashion to facilitate photoresist patterning. In oneembodiment, the proximity head may be configured to move in any mannertypically associated with a stepper mechanism as known to those knownskilled in the art. In another embodiment, the proximity head may movein a rasterized movement. In another embodiment, the proximity head(s)may be moved in a linear fashion from a center portion of the wafer tothe edge of the wafer. It should be appreciated that other embodimentsmay be utilized where the proximity head(s) move in a linear fashionfrom one edge of the wafer to another diametrically opposite edge of thewafer, or other non-linear movements may be utilized such as, forexample, in a radial motion, in a circular motion, in a spiral motion,in a zig-zag motion, etc. The motion may also be any suitable specifiedmotion profile as desired by a user as long as the desiredphotolithographic patterning of the wafer is accomplished. In addition,the proximity head and the wafer processing system described herein maybe utilized to photolithographically pattern any shape and size ofsubstrates such as for example, 200 mm wafers, 300 mm wafers, flatpanels, etc.

A fluid meniscus can be supported and moved (e.g., onto, off of andacross a wafer) with a proximity head. Various proximity heads andmethods of using the proximity heads are described in co-owned U.S.patent application Ser. No. 10/330,843 filed on Dec. 24, 2002 andentitled “Meniscus, Vacuum, IPA Vapor, Drying Manifold,” which is acontinuation-in-part of U.S. patent application Ser. No. 10/261,839filed on Sep. 30, 2002 and entitled “Method and Apparatus for DryingSemiconductor Wafer Surfaces Using a Plurality of Inlets and OutletsHeld in Close Proximity to the Wafer Surfaces,” both of which areincorporated herein by reference in its entirety. Additional embodimentsand uses of the proximity head are also disclosed in U.S. patentapplication Ser. No. 10/330,897, filed on Dec. 24, 2002, entitled“System for Substrate Processing with Meniscus, Vacuum, IPA vapor,Drying Manifold” and U.S. patent application Ser. No. 10/404,692, filedon Mar. 31, 2003, entitled “Methods and Systems for Processing aSubstrate Using a Dynamic Liquid Meniscus.” Still additional embodimentsof the proximity head are described in U.S. patent application Ser. No.10/404,270, filed on Mar. 31, 2003, entitled “Vertical ProximityProcessor,” U.S. patent application Ser. No. 10/603,427, filed on Jun.24, 2003, and entitled “Methods and Systems for Processing a Bevel Edgeof a Substrate Using a Dynamic Liquid Meniscus,” U.S. patent applicationSer. No. 10/606,022, filed on Jun. 24, 2003, and entitled “System andMethod for Integrating In-Situ Metrology within a Wafer Process,” U.S.patent application Ser. No. 10/607,611 filed on Jun. 27, 2003 entitled“Apparatus and Method for Depositing and Planarizing Thin Films ofSemiconductor Wafers,” U.S. patent application Ser. No. 10/611,140 filedon Jun. 30, 2003 entitled “Method and Apparatus for Cleaning a SubstrateUsing Megasonic Power,” U.S. patent application Ser. No. 10/738,164filed on Dec. 16, 2003 entitled “Apparatus for Oscillating a Head andMethods for Implementing the Same,” U.S. patent application Ser. No.10/918,487 filed on Mar. 31, 2004 entitled “Proximity Head HeatingMethod and Apparatus,” U.S. patent application Ser. No. 10/742,303 filedon Dec. 18, 2003 entitled “Proximity Brush Unit Apparatus and Method,”U.S. patent application Ser. No. 10/816,432 filed on Mar. 31, 2004entitled “Substrate Brush Scrubbing and Proximity Cleaning-DryingSequence Using Compatible Chemistries, and Method, Apparatus, and Systemfor Implementing the Same,” U.S. patent application Ser. No. 10/817,398filed on Apr. 1, 2004 entitled “Controls of Ambient Environment DuringWafer Drying Using Proximity Head,” U.S. patent application Ser. No.10/817,355 filed on Apr. 1, 2004 entitled “Substrate ProximityProcessing Structures and Methods for Using and Making the Same,” U.S.patent application Ser. No. 10/817,620 filed on Apr. 1, 2004 entitled“Substrate Meniscus Interface and Methods for Operation,” U.S. patentapplication Ser. No. 10/817,133 filed on Apr. 1, 2004 entitled“Proximity Meniscus Manifold,” and U.S. patent application Ser. No.10/742,303 entitled “Proximity Brush Unit Apparatus and Method.” Theaforementioned patent applications are hereby incorporated by referencein their entirety.

It should be appreciated that the methods and apparatuses discussedherein may be utilized in any suitable wafer processing system describedin the above referenced patent applications. It should also beappreciated that the lithography lens may be utilized with any suitableproximity head that can generate a stable but dynamic fluid meniscusthat can contact the lithography lens to photolithographically pattern aphotoresist on a wafer surface. The lithography lens as utilized hereinmay be any suitable type of lithographic apparatus that can transmitpatterned light through the lens to pattern a photoresist. In oneembodiment, the lithography lens can be a part of a lithographic lensstructure that is attached to a column system to form aphotolithographic light system which can include a light source, areticle, and one or more lens.

FIG. 2 shows a wafer processing system 100 in accordance with oneembodiment of the present invention. The system 100 includes a proximityhead 106 which may generate a fluid meniscus 112 as discussed herein andalso above in the U.S. patent Applications which were incorporated byreference. In one embodiment the proximity head 106 may be held by anarm 104 and be moved into close proximity above a wafer 108 that has aphotoresist 110 applied onto a top surface. The wafer 108 may have anysuitable type of layers, levels, or materials underneath the photoresist110 depending on the wafer structure(s) desired. In one embodiment, thewafer 108 may be held by a chuck 116. It should be understood that thewafer 108 may be held or supported in any other suitable manner such as,for example, by rollers holding the wafer 108 by the edges.

It should also be appreciated that the system 100 may be configured inany suitable manner as long as the proximity head(s) may be moved inclose proximity to the wafer to generate and control a meniscus whilepatterning a photoresist layer by a lithography lens structure 200 thatcontacts the fluid meniscus 112. The lithography lens structure 200 isdescribed in further detail in reference to FIGS. 3A through 4C. Itshould also be understood that close proximity may be any suitabledistance from the wafer as long as a meniscus may be maintained andpatterning of the photoresist may occur. In one embodiment, theproximity head 106 (as well as any other proximity head describedherein) may be located between about 0.1 mm to about 10 mm from thewafer 108 to generate the fluid meniscus 112 on the wafer surface. In apreferable embodiment, the proximity head 106 (as well as any otherproximity head described herein including the proximity headconfigurations described in the U.S. patent Applications referencedabove) may each be located about 0.5 mm to about 4.5 mm from the waferto generate the fluid meniscus 112 on the wafer surface, and inpreferable embodiment, the proximity head 106 may be located about 2 mmfrom the wafer to generate the fluid meniscus 112 on the wafer surface.

In one embodiment, the system 100, the proximity head 106 may be movedfrom patterned to unpatterned portions of the photoresist that has beenapplied to the wafer 108. It should be appreciated that the proximityhead 106 may be movable in any suitable manner that would enablemovement of the proximity head 106 to pattern the photoresist layer onthe wafer 108 as desired as discussed above. The proximity head 106 ofthe wafer processing system 100 may also be any suitable size or shapeas shown by, for example, any of the proximity heads as described hereinincluding those described in the patent Applications incorporated byreference above. The different configurations described herein cantherefore generate a fluid meniscus between the proximity head and thewafer, and in addition, the lithography lens structure 200 may apply apatterning light (also known as patterned light) onto the photoresist110 through a lens that is in direct contact with the fluid meniscus112. Once the light moves directly from the lens to the fluid meniscus112, depending on the refractive index of the fluid, the effectivewavelength of the light may be a much shorter effective wavelength thatthe wavelength of the light before entrance into the fluid meniscus. Itshould be appreciated that any suitable liquid that may shorten theeffective wavelength of the light applied from the lithography lens maybe used such as, for example, water, aqueous solutions of sucrose,maltose, or chloride salts, etc. By positioning the fluid meniscus indirect contact with the lens and the photoresist, refraction at themeniscus-lens interface and the liquid-photoresist interface aresignificantly reduced or eliminated. This may enable the patterned lightfrom the lens of the lithography lens to move through the meniscuswithout refraction which can reduce the effective wavelength of thepatterned light using the formula as indicated in Table 1 below.

TABLE 1$\lambda_{effective} = \frac{\lambda}{{refractive}\mspace{14mu}{index}}$

In the above equation, λ is the wavelength of the patterned light beforeentry into the fluid meniscus and λ_(effective) is the effectivewavelength of the patterned light that is applied to the photoresist ona wafer surface. In one embodiment, water may be utilized as the fluidfor the immersion lithography. Water has a refractive index of 1.43 andtherefore, if the lithography lens applies a wavelength of 193 nm to thefluid meniscus, the effective wavelength of the optical signal appliedto the photoresist may be shortened to about 135 nm. Therefore, by usinga configuration where the lithography lens directly contacts the liquidof the fluid meniscus, the effective wavelength of light from thelithography lens may be decreased significantly. The decreased effectivewavelength light hitting the photoresist on the wafer surface maypattern the photoresist into any suitable pattern desired. It should beappreciated that the light from a light source may be sent through areticle which may generate the pattern desired. The light source may beany suitable apparatus that may generate an optical signal that canpattern a photoresist such as, for example, a UV lamp, an excimer laser,etc. The reticle may be generated by any suitable method as known tothose skilled in the art.

In one embodiment, the lithography lens structure 200 is attached to apatterned light generating apparatus such as, for example, the columnsystem 202 as shown in FIG. 2. The column system 202 may be any suitableapparatus that has the light source and the reticle where unpatternedlight from the light source may be transmitted through the reticle togenerate the patterned light for transmission through the lithographylens structure 200 for patterning of the photoresist 110. It should beappreciated that lithography lens structure 200 may be any suitablestructure of any suitable configuration and/or size that is at leastpartially definable within the proximity head that can also facilitatetransmission of the patterned light signal from the column system 202 tothe fluid meniscus 112. In one embodiment, the patterned light can betransmitted from the column system 202 through the lens of thelithography lens structure 200 directly to the fluid meniscus 112. Fromthere, the patterned light can travel through the fluid meniscus 112 tothe photoresist 110 on the surface of the wafer 108. The patterned lightcan then applied to the photoresist 110 so the pattern is imposed on thephotoresist 110. Therefore, in one embodiment, the lithography lensstructure 200 can include one or more lens within a passage that extendsthrough the lithography lens structure 200 so light transmission from atop portion the proximity head 106 to a bottom portion of the proximityhead 106 is generated. It should be appreciated that the patterned lightmay be generated in any suitable fashion and the embodiments describedherein are merely exemplary in nature.

The fluid meniscus may be moved across the wafer to process the wafer byapplying fluid to the wafer surface and removing fluids from the surfacewhile at the same time applying a patterning light to the photoresist onthe wafer surface. In one embodiment, a stepper apparatus may be used tomove the lithography lens over portions of the wafer to be patterned.The wafer 108 may also be moved in a rasterized motion as thephotolithographic patterning operation progresses. It should also beappreciated that the system 100 may process one surface of the wafer orboth the top surface and the bottom surface of the wafer.

In one embodiment, the fluid meniscus 112 may be generated by applyingfluids to the wafer surface and removing the fluids from the wafersurface through conduits such as the source inlets and source outletslocated in the proximity head as described herein. It should beappreciated that conduits such as, for example, inlets and outlets, mayhave openings located on a face of the proximity head and may be in anysuitable configuration as long as a stable meniscus as described hereinmay be utilized.

In one exemplary embodiment, at least one gas inlet may be adjacent toat least one vacuum outlet which may be in turn adjacent to at least oneprocessing fluid inlet to form an gas-vacuum-processing fluidorientation. It should be appreciated that other types of orientationssuch as gas-processing fluid-vacuum, processing fluid-vacuum-gas,vacuum-gas-processing fluid, etc. may be utilized depending on the waferprocesses desired and what type of wafer processing mechanism is soughtto be enhanced. In another embodiment, the gas-vacuum-processing fluidorientation may be utilized to intelligently and powerfully generate,control, and move the meniscus located between a proximity head and awafer to process wafers. By having the ability to manage the fluidmeniscus, the lithography lens may be kept in a position so theliquid/lens interface and the liquid/photoresist interface can reducethe effective wavelength of the optical signal being applied to thephotoresist.

The processing fluid inlets, the gas inlets, and the vacuum outlets maybe arranged in any suitable manner if the fluid meniscus may begenerated and maintained in a stable manner. For example, in addition tothe gas inlet, the vacuum outlet, and the processing fluid inlet, in anadditional embodiment, there may be additional sets of gas inlets,processing fluid inlets and/or vacuum outlets depending on theconfiguration of the proximity head desired. It should be appreciatedthat the exact configuration of the gas-vacuum-processing fluidorientation may be varied depending on the application. For example, thedistance between the gas inlet, vacuum, and processing fluid inletlocations may be varied so the distances are consistent or so thedistances are inconsistent. In addition, the distances between the gasinlet, vacuum, and processing fluid inlet may differ in magnitudedepending on the size, shape, and configuration of the proximity head106 and the desired size of a process meniscus (i.e., meniscus shape andsize). Moreover, exemplary gas-vacuum-processing fluid orientation maybe found as described in the U.S. patent Applications referenced above.

In one embodiment, the proximity head 106 may be positioned in closeproximity to a top surface of the wafer 108 and may utilize the gas andprocessing fluid inlets and a vacuum outlet(s) to generate waferprocessing meniscuses in contact with the wafer 108 which are capable ofprocessing the top surface. The wafer processing meniscus may begenerated in accordance with the descriptions in reference toApplications referenced and incorporated by reference above. In oneembodiment, IPA/N₂ vapor gas may be inputted as the gas through the gasinlet and deionized water may be inputted as the processing fluidthrough the processing fluid inlet. At substantially the same time theIPA and the processing fluid are inputted, a vacuum may be applied inclose proximity to the wafer surface to remove the IPA vapor, theprocessing fluid, and/or the fluids that may be on the wafer surface. Itshould be appreciated that although EPA is utilized in the exemplaryembodiment, any other suitable type of vapor may be utilized such as forexample, any suitable vapor of alcohols (ethanol, propanol, butanol,hexanol etc.), ketones, ethers, or other organic compounds, etc. thatmay be miscible with the liquid being used to generate the fluidmeniscus the vapor of which can be carried via an inert gas. The portionof the processing fluid that is in the region between the proximity headand the wafer is the meniscus. It should be appreciated that as usedherein, the term “output” can refer to the removal of fluid from aregion between the wafer 108 and a particular proximity head, and theterm “input” can be the introduction of fluid to the region between thewafer 108 and the particular proximity head.

In one embodiment, the system 100 further includes a fluid supplydistributor that can supply to, and remove fluids from, the proximityhead 106. It should be appreciated that the fluid supply distributor maybe any suitable apparatus that can supply and receive fluids in ancontrolled manner such as, for example, a manifold. In one embodiment,the fluid supply distributor receives fluid from a fluid supply. Thefluid supply may be managed and controlled by a fluid supply controlwhich may be any suitable hardware/software that can manage fluid inputto the proximity head 106. The proximity head 106 may then produce themeniscus 112 that can process the wafer 108.

FIG. 3A illustrates a proximity head 106 with the lithography lensstructure 200 in accordance with one embodiment of the presentinvention. As discussed above, the lithography lens 200 may be connectedto any suitable apparatus that can generate the patterned light whichcan pattern a photoresist on a wafer surface. In one embodiment, asshown in FIG. 2, the patterned light generating apparatus is the columnsystem 202 that can be attached to a top portion of the lithography lensstructure 200. The lithography lens structure 200 may include a lenscapable of directly contacting the fluid meniscus to transmit thepatterned light to the photoresist through the fluid meniscus. In oneembodiment, the lens may be made from any suitable material that cantransmit the desired wavelength of light, such as, for example, CaF2,quartz, etc.

In one embodiment, the proximity head 106 includes inlets 302 and 306 aswell as outlets 304. In an exemplary embodiment of an immersionlithography operation, the proximity head 106 may produce a fluidmeniscus through which the lithography lens structure 200 may pass apatterning light to pattern the photoresist that is on the surface ofthe wafer 108 (as discussed in further detail in reference to FIGS. 3Band 3C). The inlets 302 and 306 may input any suitable surface tensionreducing gas/vapor and processing fluid respectively depending on thespecific wafer processing operation desired. An outlet 304 may generatea vacuum which can remove any suitable amount of the surface tensionreducing gas and the processing fluid (as well as any other fluid on thewafer 108) from a surface of the wafer 108. As a result, the proximityhead 106 can enable the generation of the fluid meniscus as describedherein to create a fluid medium through which a patterning light may betransmitted. In such an exemplary embodiment, the proximity head 106 mayprocess the wafer 108 so a pattern as defined by the reticle inside of acolumn structure may be transferred to the photoresist by passing thepatterned light through the lens of the lithography lens structure 200.The lens may be in direct contact with the fluid meniscus so thepatterned light from the lens may be transmitted into and through thefluid meniscus to the photoresist which may be in direct contact withthe fluid meniscus generated by the proximity head 106. When thepatterned light moves from the lithography lens to the fluid meniscus,the refractive index of the fluid meniscus may reduce the effectivewavelength of the patterned light that is applied to the photoresist.

It should be appreciated that in another embodiment of the proximityhead 106, the inlets 302 may be eliminated so just the inlets 306 andoutlets 304 remain. In such a configuration, the region where theoutlets 304 and inlets 306 are located may be indented as compared withthe rest of the processing surface of the proximity head 106.Consequently, the fluid meniscus may be contained within the indentedregion without the need to apply a confinement gas and/or a surfacetension altering gas. Therefore, a processing fluid may be inputtedthrough the inlets 306 and the processing fluid may be removed throughthe outlets 304 to generate a stable meniscus through whichphotolithography may take place.

FIG. 3B shows a side view of an internal structure of the proximity head106 in accordance with one embodiment of the present invention. In oneembodiment, the proximity head 106 includes source inlets 302 and 306 aswell as a source outlet 304. In one embodiment, as the processing fluidsuch as, for example, deionized water (DIW) is applied against the wafersurface through the source inlets 306, the fluid forms the fluidmeniscus that may be confined by the application of a gas such as, forexample, IPA/N₂ through the source inlets 302 and the vacuum 304 thatremoves the IPA/N₂ and DIW. The fluid meniscus contacts both a lens ofthe lithography lens structure 200 and the photoresist on the wafersurface to provide a medium through which the patterning light from thelithography lens structure 200 may be applied to the photoresist. In oneembodiment, the lithographic lens structure 200 includes a lens 200 athat can transmit the patterned light from the column system directly tothe fluid meniscus. As discussed above, the source inlet 302 may inputany suitable type of gas that can reduce the surface tension of theliquid that makes up the fluid meniscus. In one embodiment, the gasgenerates a surface tension gradient at a liquid/gas border of the fluidmeniscus. In one embodiment, the gas is a suitable vapor of atensioactive fluid such as those from the group of alcohols, ketones, orother organic compounds with tensioactive properties that may bemiscible with the liquid being used to generate the fluid meniscus. In apreferable embodiment, the gas is an isopropyl alcohol vapor in nitrogengas (IPA/N₂). In such an embodiment, the IPA/N₂ can reduce the surfacetension of liquids such as, for example, water. Therefore, because inone embodiment, DIW within the fluid meniscus is being constantlyreplenished, the wafer surface may be kept in a substantially cleanstate during the lithographic operation. In addition, the hardwareforming and maintaining the fluid meniscus may be configured so bubblingwithin the fluid meniscus may be kept at a minimum or eliminated alltogether thereby optimizing the patterning operation. In such a fashion,a stable meniscus may be generated that does not leave contamination onthe wafer surface because the water/gas eliminates the water beadingeffect that can leave contaminants on the wafer surface, thereby leavinga dry clean surface after processing.

In a further embodiment, the fluid meniscus may be maintained at atightly controlled temperature to control the effective wavelength;additionally, the temperature can be lowered to increase the refractiveindex of the fluid, and hence lowering the effective wavelength.

FIG. 3C shows the proximity head 106 in operation in accordance with oneembodiment of the present invention. In this embodiment, the proximityhead 106 is in operation and has generated a fluid meniscus 112 with aliquid/gas interface 388. In one embodiment, a liquid with a refractiveindex that can reduce the effective wavelength of light from thelithography lens structure 200 such as, for example, deionized water(DIW) is inputted as shown by direction arrow 314. In addition, a gasvapor such as, for example, a tensioactive gas like IPA/N₂, may beinputted as shown by direction arrow 310. The DIW and the IPA/N₂ may beremoved from the photoresist on the wafer surface as shown by directionarrow 312. In one embodiment, a vacuum is applied thereby removing theDIW and the IPA/N₂. By this method, the fluid meniscus 112 may begenerated on the wafer surface through which the lithography lensstructure 200 may apply a patterned light 400. Because the lens 200 a ofthe lithography lens structure 200 contacts the fluid meniscus 112 andthe fluid meniscus 112 contacts the photoresist, the refractive index ofthe liquid making up the fluid meniscus 112 may reduce the effectivewavelength of the patterned light 400 that is applied from thelithography lens structure 200 to the photoresist 110. In such anembodiment, the lens 200 a of the lithography lens structure 200 forms alens/liquid interface 402 with the fluid meniscus 112 and the fluidmeniscus 112 in turn forms a liquid-photoresist interface 404 with thephotoresist 110. Consequently, the patterned light 400 can travel fromthe lithography lens structure 200 through the meniscus to thephotoresist to pattern a region 390 of the photoresist 110 on the wafer108.

FIG. 4A illustrates a proximity head 106′ with an alternative exemplaryinlet/outlet configuration in accordance with one embodiment of thepresent invention. In one embodiment, the proximity head 106′ includesthe lithography lens structure 200 with source inlets 306 on one side ofthe proximity head 106′. The proximity head 106′ also includes sourceoutlets 304 on the other side of the lithography lens structure 200. Inone embodiment, source inlets 302 may substantially surround thelithography lens structure 200, the source inlets 302, and the sourceoutlets 304.

FIG. 4B shows a side view of an internal structure of the proximity head106′ with the alternative exemplary inlet/outlet configuration inaccordance with one embodiment of the present invention. In oneembodiment, the proximity head 106′ includes the lithography lensstructure 200 that includes the lens 200 a that can transmit thepatterned light generated by the column system that can be attached to atop portion of the lithography lens structure 200. The patterned lightcorresponds to the pattern desired to be generated on the photoresist onthe wafer surface to be processed. The proximity head 106′ may includesource inlets 302 and 306 on one side of the lithography lens structure200 with a source inlet 302 and source outlet 304 on the other side ofthe lithography lens structure 200. In such a configuration, liquidinputted through the source inlet 306 may be applied against thephotoresist layer on the wafer surface. The source inlets 302 may applygas to the wafer surface which in effect applies the gas against theliquid from the source inlet 306 so the liquid from the source inlets302 may be contained. The source outlet 304 may remove the liquid fromthe source inlets 302 as well as some of the gas from the source inlet302 that is on the same side as the source outlet 304. This embodimenttherefore also generates a stable fluid meniscus that facilitates thelithography operations described herein.

FIG. 4C shows the proximity head 106′ conducting lithographic operationsin accordance with one embodiment of the present invention. In oneembodiment, the proximity head 106′ has generated the fluid meniscus 112with the liquid/gas interface 388. In one embodiment, a liquid with arefractive index that can reduce the effective wavelength of light fromthe lithography lens structure 200 such as, for example, deionized water(DIW) is inputted as shown by direction arrow 314. In addition, asurface tension reducing gas such as, for example, IPA/N₂, may beinputted as shown by direction arrow 310. The DIW and the IPA/N₂ may beremoved from the photoresist on the wafer surface as shown by directionarrow 312. By this method, a dynamic fluid meniscus may be generated onthe wafer surface through which the lithography lens structure 200 mayapply a patterned light 400. The patterned light 400 may move from thelithography lens structure 200 to the photoresist through the fluidmeniscus. Because the lithography lens structure 200 contacts the fluidmeniscus 112, the refractive index of the liquid making up the fluidmeniscus 112 may reduce the effective wavelength of the patterned light400 from the lithography lens structure 200. The patterned light 400whose effective wavelength has been reduced may pattern the region 390of the photoresist on the wafer surface. In such an embodiment, the lens200 a of the lithography lens structure 200 may form the lens-liquidinterface 402 with the fluid meniscus 112 and the fluid meniscus 112 mayin turn form the liquid-photoresist interface 404 with the photoresist110. Consequently, the patterned light 400 can travel from thelithography lens structure 200 through the meniscus to the photoresistto pattern a region 390 of the photoresist on the wafer 108.

While this invention has been described in terms of several preferredembodiments, it will be appreciated that those skilled in the art uponreading the preceding specifications and studying the drawings willrealize various alterations, additions, permutations and equivalentsthereof. It is therefore intended that the present invention includesall such alterations, additions, permutations, and equivalents as fallwithin the true spirit and scope of the invention.

1. An apparatus for processing a substrate, comprising: a proximity head configured to generate a fluid meniscus to facilitate patterning of a photoresist on a substrate surface, the fluid meniscus being constantly replenished with fluid by addition of the fluid into the fluid meniscus and by removal of the fluid from the fluid meniscus by a vacuum, the proximity head having source inlets that introduce a surface tension reducing gas, the surface tension reducing gas being configured to reduce surface tension of the fluid meniscus relative to the substrate surface, and the proximity head further having a head surface that has flat surface regions, the head surface is defined with discrete holes to pass the fluid, the vacuum, and the surface tension reducing gas, the discrete holes reside at the head surface and extend through the flat surface regions of the head surface; and a lithography lens structure at least partially defined within the proximity head, the lithography lens structure having a lithography lens configured to be in direct contact with the fluid meniscus during operation, the lithography lens structure configured to apply a patterned light from the lithography lens through the fluid meniscus to pattern the photoresist on the substrate surface.
 2. An apparatus for processing a substrate as recited in claim 1, wherein the lithography lens structure is attached to a column system which includes a light source and a reticle for generating the patterned light.
 3. An apparatus for processing a substrate as recited in claim 1, wherein the proximity head includes a plurality of conduits capable of defining the fluid meniscus.
 4. An apparatus for processing a substrate as recited in claim 2, wherein the lithography lens is substantially surrounded by the plurality of conduits.
 5. An apparatus for processing a substrate as recited in claim 1, wherein the fluid has a refractive index greater than
 1. 6. An apparatus for processing a substrate as recited in claim 1, wherein the patterned light has a first wavelength before entering the fluid meniscus, and the patterned light when transmitted through the fluid meniscus and applied to the photoresist has a effective wavelength shorter than the first wavelength.
 7. An apparatus for processing a substrate as recited in claim 3, wherein the plurality of conduits includes at least one of a first inlet for applying the fluid to the photoresist, the source inlets for applying the surface tension reducing gas to the photoresist, and an outlet for removing the fluid and the surface tension reducing gas from the photoresist.
 8. An apparatus for processing a substrate as recited in claim 7, wherein the surface tension reducing gas is a vapor gas that promotes a surface tension gradient at a border of the fluid meniscus.
 9. An apparatus for processing a substrate as recited in claim 8, wherein the vapor gas is one of an alcohol vapor, a ketone vapor, and an ether vapor in an inert gas.
 10. An apparatus for processing a substrate as recited in claim 8, wherein the vapor gas is IPA/N₂.
 11. An apparatus for processing a substrate, comprising: a proximity head capable of generating a fluid meniscus to process a photoresist on a substrate surface, the fluid meniscus being constantly replenished with fluid by addition of the fluid into the fluid meniscus and by removal of the fluid from the fluid meniscus by a vacuum, the proximity head having source inlets that introduce a surface tension reducing gas, the surface tension reducing gas being configured to reduce surface tension of the fluid meniscus relative to the substrate surface, and the proximity head further having a head surface that has flat surface regions, the head surface is defined with discrete holes to pass the fluid, the vacuum, and the surface tension reducing gas, the discrete holes reside at the head surface and extend through the flat surface regions of the head surface; and a light generating source at least partially defined within the proximity head, the light generating source configured to be in direct contact with the fluid meniscus during operation, the light generating source capable of applying a patterned light into and through the fluid meniscus, the patterned light having a first wavelength before entrance into the fluid meniscus and an effective wavelength when applied to the photoresist through the fluid meniscus, the effective wavelength being shorter than the first wavelength.
 12. An apparatus for processing a substrate as recited in claim 11, wherein the light generating source comprises a column system and a lithography lens structure, the column system including a light source and a reticle for generating the patterned light, lithography lens structure including a lens configured to be in direct contact with the fluid meniscus in operation and further configured to directly apply the patterned light to the fluid meniscus.
 13. An apparatus for processing a substrate as recited in claim 12, wherein the lens is substantially surrounded by a plurality of conduits.
 14. An apparatus for processing a substrate as recited in claim 11, wherein the proximity head includes a plurality of conduits capable of defining the fluid meniscus.
 15. An apparatus for processing a substrate as recited in claim 14, wherein the plurality of conduits includes at least one of a first inlet for applying the fluid to the photoresist, the source inlets for applying the surface tension reducing gas to the photoresist, and an outlet for removing the fluid and the surface tension reducing gas from the photoresist.
 16. An apparatus for processing a substrate as recited in claim 15, wherein the surface tension reducing gas is a vapor gas that promotes a surface tension gradient at a border of the fluid meniscus.
 17. An apparatus for processing a substrate as recited in claim 16, wherein the vapor gas is one of an alcohol vapor, a ketone vapor, and an ether vapor in an inert gas.
 18. An apparatus for processing a substrate as recited in claim 16, wherein the vapor gas is IPA/N₂.
 19. An apparatus for processing a substrate as recited in claim 11, wherein the fluid meniscus is made up of a liquid with a refractive index greater than
 1. 20. A photolithography apparatus, comprising: a proximity head, the proximity head being capable of generating a meniscus on a surface of a substrate, the proximity head having source inlets that introduce a surface tension reducing gas, the surface tension reducing gas being configured to reduce surface tension of the fluid meniscus relative to a substrate surface and the proximity head further having a head surface that has flat surface regions, the head surface is defined with discrete holes to pass a fluid, a vacuum, and the surface tension reducing gas, and the discrete holes reside at the head surface and extend through the flat surface regions of the head surface; and a light source for applying photolithography light from the proximity head and through the meniscus, the photolithography light being configured to contact the surface of the substrate to enable photolithography processing.
 21. An apparatus for processing a substrate as recited in claim 20, wherein the proximity head includes a plurality of conduits capable of defining the meniscus.
 22. An apparatus for processing a substrate as recited in claim 20, wherein the meniscus is made up of a liquid with a refractive index greater than
 1. 